This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We are investigating the details of cation binding to DNA quadruplexes and DNA-ligand complexes as determined by Circular dichroism, Nuclear Magnetic Resonance (NMR), as well as computational methods. The analysis of these structures requires use of Chimera, MidasPlus, and Sparky, (all developed within the RBVI) as well as other programs. Chimera is also used to help visualize results and to obtain views and structural comparisons.